An interesting scenario - I didn’t know there had been Belgian involvement in East Africa.
How well do you find BBB works for WWI? I mainly ask as the lines of troops don’t quite look WWI, but I know when we play ITLSU we end up with loose lines of bases for units, so its not far off the look we get from a pure WWI ruleset, even though it is a representative level or two lower.
You bring up a good point about proxies, not sure who would have picked the Belgian proxies without being told, the Boers for Germans stand out a bit more (would Boer War British have worked any better, on the proxy front?).